The induced synthesis of metallothionein in various tissues of rat in response to metals. I. Effect of repeated injection of cadmium salts.

Even though the induce synthesis of metallothionein (MT) after exposure to metals has been known for some time, there is little data on the quantitation of MT in various tissues. In this study we have measured MT levels in eleven different tissues of rat after injection of CdCl2 and also compared the relative MT inducibility of these tissues. Over a period of 16 days, rats were injected subcutaneously once every second day with either saline or 3 different doses - 0.8, 1.5 or 3 mg (7.2, 13.4 or 26.8 mu mol) Cd/kg of CdCl2 and sacrificed 48 h after the last injection. Cadmium and MT were determined in brain, lung, heart, liver, kidney, stomach, small intestine, pancreas, spleen, testes and muscle. A dose dependent increase in MT accumulation was observed in a number of tissues after CdCl2 injection, the highest amount being in liver, kidney and pancreas. Further analysis of the data showed a positive correlation between Cd and MT concentrations in 8 tissues. The relative MT inducibility in liver, pancreas, heart and stomach in response to Cd injection was identical.